This invention relates to improvements in method for making reclosable bags, and is more particularly concerned with a method especially suitable for making reclosable bags from one piece integral extrusions, and which are adapted to be initially hermetically sealed and after being opened are reclosable by means of integral separable fasteners.
A wide variety of products from foodstuffs to hardware and materials in liquid or granular form are desirably packaged in flexible plastic bags which may or may not be transparent or at least translucent. With certain types of packaged contents, it is desirable to provide means preventing unauthorized access to the contents or to prevent spillage. Often the contents must remain hermetically sealed until used. With pourable contents, whether liquid or particulate, it is often desirable to have the bags equipped with pouring spout means. A type of bag which is especially suitable for these purposes is disclosed in U.S. Pat. No. 3,746,215. However, the bags disclosed therein are constructed from a plurality of separately formed parts secured together. That complicates and increases cost of manufacture because of the multi-part fabrication and the necessary assembling and securing together of the parts.
A principal aim of the present invention is to provide a new and improved, simplified, efficient method by which the bags can be produced in one integral extruded piece. Tubular extrusions for manufacture of bags are disclosed, for example, in U.S. Pat. Nos. 3,246,672, Re. 29,208, and 3,380,481. Although those patents disclose the integral extrusion of separable zipper-type resiliently flexible fasteners, they fail to have any provision for a combination closure and hermetic sealing gusset means which may, if desired also provide pouring spout means.